Attaching clip for control knobs



Nov. 21, 1944. NIRDUNGER 2,363,194

ATTACHING'CLIP FOR CONTROL KNOBS w Filed Oct. 25, 1943 INVENTOR 75%) )VzrJZz I758)? ATTO Patented Nov. 21, 1944 l w $353,194 ATlI-AOHING omrl romcolvrnoi. KNOBS "John Nlrdlinger. "Detroit, Mich, "assignor to 'D'etrola Got-notation, Detroit, Mich, a corporation or Michigan ApplicationDctober 25. 1943, Serial 1\n .51i7,ess

W u -1 Claim. (c1. newts) This invention z'relates to' means .for detachably attaching control handles or-knobs .to shafts and the like, and is particularlyuseful in attaching the control knobs to the tuning condenser and volume "and switch control shafts :of radios.

The main objects "of this invention are to: PIOrvidelimproved means for detachably atta'ching a control knob toia shaftso asxto-be rotatably fixed with respect 1 theretopbut whichzlpermits thesis-nob to be readilyand (easily assembled-to or removed fromlthe "shaft bymovemen tinan axial direction to provide: improved means of this character which willnot ='loosen:up through use as -joften happens withrset screws heretofore commonly used for this purpose; "and to provide means of this character whichepermits-thecontrol-knobs to be securelyfiassembledon the shafts without the useof a screw driver or other tool.

An illustrative embodiment of this invention-is it shown'inthe accompanying drawing in which:

Figure 1 is a view, partly in elevation and partly in section, of a control knob detachably secured to the serrated end of a. shaft by means of the improved clip which is the subject matter of this invention;

Fig. 2 is a sectional view taken on the line 2-42 of Fig. 1, looking in the direction indicated. by the arrows; l l

i Fig. 3 is a longitudinal sectional view of the control knob shown in Fig. 1, illustrating the shape and extent of the shaft and clip-receiving opening therein; l q

Fig. 4 is aview in elevation of the control knob shownin Fig. 3, taken from the open or right hand end jasviewed in that figure; Fig. 5 is a top plan taching clip; j 3

Fig. 6 is a View in end edge elevation ofthe same; if l Fig. "7 is a view in side edge elevation of the same. I l I In the manufacture and construction of devices particularly suchas radios and the like it has heretofore been customary to attach the control knobs to the variable condenser shafts and to the switch and volume control shafts by pro-.

viding the knob with a longitudinally extending or axially. disposed bore to receive the protruding shaft end and then providing the knob with a radially disposedset screw for frictionally gripping or engaging the shaft. The use of such construction presents a problem both in the assembly of the radio as well as duringthe use of the machine. In the assembly it is necessary to insert these relatively small set screwstinto thethreaded openings in. the

knobs i and then, when *assembled on their ;re-

spective 1 shafts, Itightenthe set screws down onto the ishaft'by meansof a' screw driver. Frequently during the use ofthezradiothese control knobs become loose andkevery operator orowner of a radio s'et is not i equipped with a sufficiently-small screw 'drivenfor retightem'ng them.

. In the present construction (both for the fore going 'difficulties have been overcome in that the control knob maybe applied toits shaft irr'a fraction of 1 the time' required*to attach the. prior type and at the same timedoiitwi-thout the .use of any tools such asa screw driver or the'like. Also the con trol knob, while in --position on its-shaft, is at all times fixedorlocked-tagainst rotation relative to itsf-shaft andcthereiis no part whiichvmay w'o'rk loose and give trouble asin the case with the use 'of a set screw. Furthermore, the use of the improved attaching clip disclosedherein-permits the control knob to be readily and quickly removed from its shaft without the aid of a screw driver or other tool, by simply grasping the control knob and pulling it in a direction axially of its shaft;

In the construction shown in the drawing, a control knob 8 is shown provided with an axially disposed circular bore ll] of suchsize as to snugly receive the end of a shaft l2. The end of the shaft [2 which extends into the control knob is preferably provided on its exterior surface with view. of the improved atp a plurality of closely spaced serrations M.

w The knob 8 has the bore Ill enlarged or cut away as most clearly shown in Figs. 2 and 4, to

provide a substantially fiat seat lfi-disposed sym metricallywith respect to the axis of the bore l0 and spaced from the circumference thereof a predetermined amount as shown. at Ill. The seat [0 extends axially to a point adjacent the lefthand end or bottom of the bore 10 as shown most clearly in Fig. 3, and the lateral edges thereof are formed to provide shallow groovesZl and 22. The side walls adjacent said grooves slope or converge toward each other as shown at 24 and Z6 respec- 'tively and terminate tangentially with respect to the circumference of the bore l0. The improved attaching clip comprises a sheet (metal plate 28 formed of a springy or resilient metal and has two pairsof aligned semi-circular ears or tabs 30 and 32 struckup fromthe surface of the plate into opposed inclined position as shown most clearly in Figs. 2 and 6. The plate 28 also ha a similar struck-out earor tab 34 protruding from the opposite side thereof, forming a l relatively smaller or lesser angle with respect to the plane of the plate.

The plate 28 is of substantially the same width as the width of the seat I6 so that the grooves 20 and 22 snugly embrace the side edges of the plate when inserted into the opening on the seat I6. The length of the plate 28 is substantially equal to the depth of the seat l6 axially of the knob 8, so that the plate is completely housed within the knob. The metal from which the plate orclip 28 is made is substantially of the same thicknes as,

the space I8 so that the top surface of the plate or clip, when in position on its seat, will snugly contact the outer periphery of the knurled end M of shaft I2.

The upstanding ears or tabs 30 and 32 are of such dimension and are so positioned that when the clip or plate 28 is in position on its seat l6, the upper end edges of these tabs or ears will enter and snugly engage the grooves formed by the serrations l4 as shown most clearly in Fig. 2. The tab 34 engages the floor of the seat I 6 when the clip is inserted into the knob and acts as a barb to dig or bite into the floor of the clip seat and thereby prevent the ready removal of the clip from the knob when assembled therein. This biting into the floor of the seat is further facilitated by pressure of the shaft l2 against the top surface of the clip which tends to force or urge the tab 34 downinto the material of the clip seat.

In the use of this device the plate or clip 28 is inserted into the knob 8 prior to assembly on the shaft l2 with the locking tab 34 extending toward the open end of the knob as shown in Fig. 1. The assembly of control knob and clip is then mounted on the serrated end of the shaft I2 by simply pressing it into place by movement in an axial direction, thereby engaging the upstanding tabs or ears 3!] and 32 in the grooves formed by the serrations I4. 7

When in this position, rotation of the knob in either direction will rotate the shaft 12 and slippage in either direction is prevented at ll times by reason of the opposed positions of the locking tabs or ears 30 and 32.

Removal of the knob from the shaft may be accomplished readily at any time by simply grasping the knob .and pulling axially relative to the shaft l2, the locking tab or ear 34 preventing the clip from coming out of the knob 8 during such ;removal of th knob and thereafter unless it is desired to specifically remove the clip from the knob. This may be done by inserting a thin wedge instrument under the center of the clip, thus springing it or bowing it up slightly in the middle.

and permitting its removal from the seat and edge-engaging grooves of the knob 8.

Although one specific embodiment of this invention has been herein shown and described, it

will be understood that details may be altered, omitted, or exemplified, without departing from the spirit of this invention, as defined by the fol;

lowing claim.

What is claimed is: d I In the combination of a shaft having a serrated end and control handle for rotating same, a substantially flat sheet metal spring clip seated in said handle-so as to be rotatably fixed with respect thereto, a pair of ears struck out from one surface thereof, said, ears being oppositely inclined with respect to each other and disposed in a direction between radial and tangential relative to said shaft, and the outer free end edges of said ears having bearing relation against the serrated end of said shaft for exerting a biasing force thereagainst, and an ear struck out from the other surface thereof forengaging the handle so as to prevent easy removal of said clip from said handle.

JOHN NIRDLINGER. 

